Interzonal herbivores, which make up the main mass of the summer 

 plankton, are rather evenly distributed in the winter over depths of 

 more than 200 m throughout the entire cold-water portion of the sea. In 

 the spring, they migrate to the surface layer, where their biomass 

 rapidly increases, and in the summer, over most of the water area, their 

 biomass is at least 5 kcal/m^ (Fig. 7). The seasonal dynamics of the 

 spatial distribution of the boreal omnivorous mesoplankton, in its most 

 general features, repeats the distribution of interzonal herbivores, but 

 with significantly lower biomass. 



The distribution of southern forms of zooplankton (Fig. 7) is 

 determined basically by the temperature conditions and mode of the 

 Tsushima Current. In winter, their main mass is concentrated along the 

 coast of Japan. In spring, heating begins and the arrival of warm water 

 and zooplankton from Tsushima Strait increases, reaching its maximum in 

 fall. As a result, during the fall the area of distribution of the 

 southern forms of zooplankton covers almost the entire southeastern 

 portion of the sea. 



The migration of nektonic animals (fish and squid) begins in the 

 spring in the southern portion of the Sea of Japan and follows 2 main 

 tracks: the more numerous stream is directed along the Honshu coast to 

 the northeast, the less numerous stream--along the coasts of Korea 

 toward Petr Velikiy Bay. In the summer and fall, significant numbers of 

 squid, according to the data from the model, are observed in the central 

 portion of the sea in the zone of contact between the Primorskiy and 

 Tsushima Currents (Fig. 7). 



Unfortunately, there are no sufficiently complete data available on 

 the true distribution of the biomass of phytoplankton, bacterioplankton 

 and zooplankton, fish and squid in the water area of the Sea of Japan in 

 the seasonal aspect. Therefore, the question of the degree of accuracy 

 of the model which has been created remains open, although we can note 

 that the picture of distribution of zooplankton obtained in the model is 

 not contradicted by the available (though rather fragmentary) 

 observations of the distribution of its biomass. The distribution of 

 squid also agrees in general terms with the observed distribution 

 (Zuyev, Nesis, 1971). 



The model in question shows the actual possibility of quantitative 

 description of the seasonal changes and distribution over a water area 

 of elements of a pelagic ecosystem. Obviously, models of this type can 

 yield not only production, but also zoogeographic information. The 

 separation of species of boreal and warm-water complexes in the model of 

 the Sea of Japan is a step in this direction. 



It must be considered that models of this type are quite sensitive 

 to the quality of hydrologic data used. The need not only for a general 

 diagram of currents, but also for values of mass transfer in each square 

 of the water area, as well as precise values of the coefficient of 

 horizontal turbulent diffusion, places certain limitations on the area 

 of application of such models. 



338 



